Finding Rational Numbers: Easy Examples & Steps

by Alex Johnson 48 views

Finding rational numbers between two given numbers is a fundamental concept in mathematics. This article will guide you through the process with clear examples and explanations, making it easy to understand and apply. We'll explore how to find three rational numbers between two integers and between two fractions, providing step-by-step solutions and insights.

(i) Finding Three Rational Numbers Between 4 and -3

When tasked with finding rational numbers between two integers, like 4 and -3, the process is quite straightforward. Rational numbers are numbers that can be expressed in the form p/q, where p and q are integers and q is not equal to zero. Integers themselves are rational numbers since they can be written as the integer divided by 1 (e.g., 4 = 4/1). To find rational numbers between 4 and -3, we can simply identify integers that lie between them or create fractions that fall within this range. Let's dive deeper into this.

First, it's helpful to visualize the number line. On a number line, integers between 4 and -3 are 3, 2, 1, 0, -1, and -2. These are all rational numbers. To find three rational numbers, we can select any three from this set. For example, we can choose 3, 1, and -1. These numbers clearly fall between 4 and -3. Alternatively, we could include fractions. For instance, 0.5 (or 1/2) is a rational number between 0 and 1, which also lies between 4 and -3. Similarly, -0.5 (or -1/2) lies between -1 and 0, fitting within our specified range.

Another approach is to take the average of the two numbers to find a rational number between them. The average of 4 and -3 is (4 + (-3))/2 = 1/2 = 0.5. This confirms that 0.5 is a rational number between 4 and -3. We can repeat this process to find more rational numbers. For example, the average of 4 and 0.5 is (4 + 0.5)/2 = 4.5/2 = 2.25, which is another rational number between 4 and -3. Similarly, the average of -3 and 0.5 is (-3 + 0.5)/2 = -2.5/2 = -1.25, also a rational number in the desired range. By using this averaging method, we can generate an infinite number of rational numbers between any two given numbers.

In summary, finding rational numbers between two integers involves identifying integers or fractions that lie within the given range. Common methods include listing integers, creating simple fractions, or using the averaging technique to find intermediate rational numbers. This concept is fundamental in understanding the density of rational numbers on the number line.

Thus, three rational numbers between 4 and -3 are: 3, 1, and -1.

(ii) Finding Three Rational Numbers Between $-\frac{7}{11}$ and $\frac{5}{6}$

Finding rational numbers between two fractions, such as $-\frac{7}{11}$ and $\\frac{5}{6}$, requires a slightly different approach compared to finding rational numbers between integers. The key here is to find a common denominator so that we can easily compare and identify intermediate rational numbers. Let's break down this process step by step to make it clear and manageable.

First, we need to find the least common multiple (LCM) of the denominators 11 and 6. The LCM of 11 and 6 is 66. Now, we convert both fractions to equivalent fractions with a denominator of 66. To do this, we multiply the numerator and denominator of $-\frac{7}{11}$ by 6, resulting in $-\frac{42}{66}$. Similarly, we multiply the numerator and denominator of $\\frac{5}{6}$ by 11, resulting in $\\frac{55}{66}$. Now we have two fractions, $-\frac{42}{66}$ and $\\frac{55}{66}$, which are much easier to compare.

Next, we look for rational numbers between $-\frac{42}{66}$ and $\\frac{55}{66}$. Since the denominators are the same, we can focus on finding integers between -42 and 55. Several integers lie between these two numbers, such as -41, -40, -39, ..., 0, 1, 2, ..., 54. We can choose any three of these integers and place them over the common denominator 66 to form rational numbers between the two original fractions. For example, we can choose -40, 0, and 50. This gives us the rational numbers $-\frac{40}{66}$, $\\frac{0}{66}$, and $\\frac{50}{66}$. Simplifying these fractions, we get $-\frac{20}{33}$, 0, and $\\frac{25}{33}$. These are three rational numbers between $-\frac{7}{11}$ and $\\frac{5}{6}$.

Another approach is to find the average of the two fractions to get a rational number between them. The average of $-\frac7}{11}$ and $\\frac{5}{6}$ is ((-7/11) + (5/6))/2 = ((-42/66) + (55/66))/2 = (13/66)/2 = 13/132. So, 13/132 is a rational number between $-\frac{7{11}$ and $\\frac{5}{6}$. We can repeat this process to find more rational numbers. For instance, we can find the average of $-\frac{7}{11}$ and 13/132, or the average of 13/132 and $\\frac{5}{6}$, to get additional rational numbers in the specified range.

In conclusion, finding rational numbers between two fractions involves finding a common denominator, identifying integers between the numerators, and placing these integers over the common denominator. Alternatively, the averaging method can be used to generate rational numbers between the given fractions. This method allows us to find an infinite number of rational numbers between any two given fractions, demonstrating the density of rational numbers.

Thus, three rational numbers between $-\frac7}{11}$ and $\\frac{5}{6}$ are $-\frac{40{66}$, $\\frac{0}{66}$, and $\\frac{50}{66}$.

Understanding how to find rational numbers between any two given numbers is a key concept in mathematics. By using methods such as finding common denominators and averaging, you can easily identify or generate an infinite number of rational numbers within any given range. This skill is valuable for various mathematical applications and provides a deeper understanding of the number system.

For further reading on rational numbers, you can visit Khan Academy's Rational Numbers Section.